Economical Ideas:
I bought ten five gallon pails from Home Depot. They are about $3 each. I found some scrap wood to "lift" them up an inch or so above the floor for sound purposes and we used drum sticks on them. My students really enjoyed this.

Call you local Culligan dealer. They have 5 gallon "leakers" that they will usually give you for free. Turn them upside down and hug them with your knees -awesome!

I got the 5 gallon pails from our kitchen when they were done with them. Didn't cost me a nickle!

classroom set of these:

-tone blocks and wood blocks
-rhythm sticks
-hand drums
-triangles
-castanets
-tambourines
-finger cymbals
-claves
-jingle taps
-jingle bells

It's also great to have a couple of the following:
-vibra-slap
-guiro
-cabasa
-gong
-train whistle

Several summers ago I witnessed a drum circle that the Indianapolis Symphony had on the sidewalk in front of their building during the lunch hour on Fridays. It was wonderful to watch. Several rows of chairs were placed in a circle with an instrument in front of each chair. One of their staff who had been trained in facilitation led the circle. Many people would join the circle during their lunch time. Some for as little as a couple of minutes. Other for much longer. They had a large number of drums and other small instruments however they also supplemented their instruments with buckets. After watching this, I went out and purchased 20 buckets in primary colors. Then I purchased Vic Firth drum circle sticks. They are shorter then regular drum sticks and shaped like rhythm sticks. You buy them by the dozen and they come in a package of mixed primary colors (red, blue, yellow, and green.) They are very reasonable compared to
drum sticks and because they don't taper, last for ever. I now use them on my wood blocks as well.